Preparation, characterization, and in vitro release study of curcumin-loaded cataractous eye protein isolate films

Abstract

Curcumin, a naturally occurring polyphenol despite having therapeutic properties, has limited application due to its poor solubility in aqueous medium. The aim of this study is to explore a new protein source developed as a protein film, for the delivery of curcumin. The cataractous eye protein isolate (CEPI) is a mixture of proteins obtained after phacoemulsification surgery of the eye lens. The films have been prepared from the discarded CEPI and investigated for potential applications as a delivery system for curcumin. The films were prepared using glycerol as the plasticizer and glutaraldehyde as the cross-linker. The mechanical properties of the films were monitored by using nanoindentation techniques (NINT). The curcumin-loaded films were characterized by Fourier transform spectroscopy (FTIR), field emission scanning electron microscopy (FESEM), and thermogravimetric analysis (TGA) which established the incorporation of curcumin in the protein matrix. The loading efficiency of the films was found to be dependent on the degree of cross-linking of the films. In vitro release studies showed an initial burst release followed by a sustained release. The release rate is higher at pH 4.5 compared with pH 7.4. The released aliquots of curcumin-loaded films also exhibit antibacterial effects against Staphylococcus aureus. Our findings will be generally beneficial for the further reshaping of protein films as potential delivery carriers.